C＃SQLCommand count（*）仅在通过sql数据适配器检索时返回0

Question

尝试通过数据适配器检索一些数据并最终解析为json。但count（*）操作总是返回0.当直接在DB中运行相同的查询时，我会收到正确的值。

我只看到了使用ExecuteScalar函数检索的SQL count（*）函数的示例，因此不确定这是否是我唯一的选择。

try 
{
  using (SqlConnection connection = new SqlConnection(ConnectionStr))
  {
    connection.Open();
    using (SqlCommand sqlCommand = new SqlCommand())
    {
       sqlCommand.Connection = connection;
       sqlCommand.CommandText="SELECT 'Year  > 2010' AS YEAR_BUILT, COUNT(*) AS VALUE " +
       " FROM STRUCTURE AS STRUCTURE " + 
       " WHERE (YR > 2010) " +   
       " UNION ALL " + 
       " SELECT 'Year Between 2000 - 2010' AS YEAR_BUILT, COUNT(*) AS VALUE " +  
       " FROM STRUCTURE AS STRUCTURE " +
       " WHERE (YR BETWEEN 2000 AND 2010) " ;

       using (SqlDataAdapter dataAdapter = new SqlDataAdapter(sqlCommand))
       {
          DataTable dataTable = new DataTable();
          dataAdapter.Fill(dataTable);  // Value always returned as 0 .
          sqlCommand.Dispose();
          return dataTable;
       }
    }
 }
}
.....